The D2 from iBasso splices two pieces of high-end audio gear into audiophile matrimony. Comprising both an external USB sound processor (DAC) for your PC or Mac, and an impressive headphone amplifier, the D2 has for the past month replaced our beloved Woo Audio 2 amplifier.

The question we know you're asking is, could I expense one to the government? The answer is of course, as long as you're an MP. Otherwise it'll cost you £165 of your own money from hifiheadphones.co.uk.

So why the hell do I need something like this anyway?

Because if you need a sound card for your computer, and you've spent money on a decent pair of headphones, it'll make your music sound better. Here comes a suitable analogy: a great dSLR camera will work great with the lens that comes in the box. But invest in a better lens and you get better pictures.

The D2's sound processing is handled by a Wolfson WM8740 chip, which is responsible for a great deal of the audio quality from Arcam's stellar-sounding Solo Mini, and its high-end CD and DVD players. The resulting sound from the D2 is beautiful -- crisp, controlled and powerful.

When compared to sound quality from a MacBook, the D2 deepened and smoothed out the bass, gave vocals a significantly richer, velvety-smooth quality and extended the high-end. Without question, as long as your headphones are capable of conveying it, the D2 makes a difference audiophiles will happily pay for.

There's a line-in socket as well if you just need to use the amp rather than the DAC. Any 3.5mm audio source can be jacked in here, but you'll only get the audio-processing functions if you hook up via USB.

Beware: if you're just using bundled iPod earbuds or something similar, there's no point wasting your money. The difference in sound quality you'll hear is practically non-existent. In fact, we can't honestly say the difference was enormous even through Klipsch's X5 earphones. The benefit here is with large headphones, particularly higher-impedance models such as Sennheiser's HD 650s.

Oh, did we mention you can power it from an internal battery, too? Yeah, that's a big fat whoop-de-whoop bonus right there. You're not going to want it in your pocket, but sitting on a desk it's handy. It's charged over USB and you'll get about 30 hours of playback from a full charge.

Overall, it's a stonking piece of kit, and well priced if you need a DAC and a headphone amp. If you were thinking about this as a hi-fi component, be aware there's no line-level output or a TosLink input, so it's not ideal. An iBasso D10 (which we're currently testing) is what you'll need for that.

Check some photos over the next few pages for detail shots, or go and order one from hifiheadphones.co.uk.